Biochar plus urine results in highest yield

The results from adding biochar to test plots in Bungoma County, Western Kenya, have been published by Re-Char.

• Plain soil (without chemical fertilizer or organic amendment) produced around 70 kg of dry sorghum per acre.
• A 15% solution of sanitized urine and water added to soil gives a sorghum yield of 205 kg per acre.
• Adding 50 kg of chemical fertilizer per acre– the Kenyan Government’s recommended quantity– can increase yield of sorghum to 420 kg per acre.
• By applying 6,000 kg per acre of composted cow manure, farmers can produce 810 kg of dry sorghum per acre.
• Applying the above urine treatment to soils amended with biochar (at a rate of 6,000 kg per acre) resulted in a sorghum yield of 533 kg per acre in season 1, and 1,025 kg per acre in season 2 without adding any additional biochar.

The data are presented below in an interactive graph (move mouse over bars to view data).
This highlights biochar's potential to help achieve higher crop yields than chemical fertilizers, while biochar has the additional benefit of helping combat climate change by avoiding emissions, such as of carbon dioxide, methane, carbon monoxide and soot. Moreover, adding biochar and olivine sand to the soil results in additional vegetation growth that takes carbon dioxide out of the atmosphere, while safely storing carbon in soils.

Chemical fertilizers cause large nitrous oxide emissions and make farmers dependent on their continued supply, which can be hard given variations in farming income and in the price of the fossil fuel that is typically used to produce the chemical fertilizers. Long supply lines and extensive transportation and infrastructure requirements that are vulnerable to extreme weather events can significantly increase the cost of chemical fertilizers. By contrast, biochar and urine can be produced locally from waste products at little or no extra cost to local farmers.

Feebates are recommended as the best policy instruments to achieve the necessary changes, as part of a comprehensive and effective climate plan. The image below pictures feebates in agriculture, land use and construction. Fees are imposed on sales of Portland cement, with revenues used to fund rebates on clean construction methods that incorporate olivine sand. Similarly, fees are imposed on Portland cement, on nitrogen fertilizers and on livestock products, with revenues used to fund rebates on soil supplements containing olivine sand and biochar.

From:  President Obama, here's a climate plan!

Combined, biochar and olivine sand can help soils become more fertile. Applying olivine dust on top of biochar can also reduce the albedo impact of biochar, which can be substantial as described in a 2012 study by Meyer et al. Thus, biochar and olivine sand can complement each other in several ways, as discussed earlier in the post Towards a Sustainable Economy.